Production of cyclic alkene



United States Patent 3,369,052 PRODUCTION OF 'CYCLIC ALKENE Frederick Harold Howell, Maghull, and Wilfred Pickles,

Hazel Grove, England, assignors to Geigy Chemical Corporation, Ardsley, N.Y., a corporation of New York No Drawing. Continuation-impart of application Ser. No.

405,838, Oct. 22, 1964. This application Dec. 5, 1966,

Ser. No. 598,924 Claims priority, application Great Britain, Oct. 29, 1963,

42,632/ 63 5 Claims. (Cl. 260-666) ABSTRACT OF THE DISCLOSURE Cyclododecene is produced from cyclododecatriene in at least 80% yield by heating cyclododecatriene to a temperature of l30180 C. at atmospheric pressure without solvent, catalysing the reaction with a palladium hydrogen catalyst.

This application is a continuation-in-part of our application Ser. No. 405,838, filed Oct. 22, 1964; now abandoned.

The present invention relates to the production of unsaturated cycloaliphatic organic compounds and particularly to the production of a cycloalka-mono-ene from a more highly unsaturated cyclic alkene.

More particularly, this invention relates to the production of cyclododecene from cyclododecatriene.

Cyclododecene is a useful intermediate in the production of other valuable organic compounds.

Cyclododecene may be oxidised by known methods at the ethylenic double bond to produce 1:12-dodecanedioic acid, esters of which are of value as plasticisers or as constitutents of synthetic lubricants or other functional fluids.

Cyclododecene can be produced in various ways, but generally with very low yields, for instance, by ring condensation and reduction, the yield rate being about 0.5%. Partial hydrogenation of cyclododecatriene recommends itself in view of the industrial availability of the triene. However, in doing so the problem arises how to obtain a satisfactory cyclododecene content in the resulting mixed hydrogenation product which consists essentially of fully hydrogenated cyclododecane, the desired cyclododecene, cyclododecadiene and unreacted cyclododecatriene.

For the above-stated purposes, cyclododecene should be present in the reaction product preferably in amounts of 90% by weight, or higher, but lower contents, above about 80% by weight, are also acceptable if the content of diene and unreacted triene does not exceed to by weight. Otherwise, the workup of the reaction product becomes too involved.

A process for the selective hydrogenation of cyclododecatriene to cyclododecene has already been proposed, Wiese et al., US. Patent 3,022,359. This known process employs a high surface area catalyst in combination with 'adisplacement solvent to achieve the desired selective hydrogenation. The source of hydrogen in the Wiese et al. process may be gaseous hydrogen, a hydrogen transfer agent or a mixture thereof. However this known process in order to achieve satisfactory selectivity, employs only a secondary alcohol hydrogen transfer agent as the hydrogen source since such a hydrogen transfer agent is converted to a ketone and the ketone then acts as a displacement solvent. As high surface area catalysts to be used in combination with the hydrogen transfer agent there are named, primarily, Raney nickel, and further nickel deposited on kieselguhr, alumina or silica; as well as iron, cobalt, copper, palladium, platinum, molybdenum, tungsten and chromium.

3,369,052 Patented Feb. 13, 1968 The data in the aforesaid U.S. patent show clearly that high selectivity to cyclododecene combined with a high conversion of cyclododecatriene starting-material is only achieved when a secondary alcohol is used as the sole source of hydrogen in combination with nickel as catalyst and when the reaction is effected under high pressure. In those experiments carried out solely for comparative purposes in which Wiese et-al. used only gaseous hydrogen as the hydrogen source, a nickel or platinum catalyst and no displacement solvent, very unsatisfactory selectivity to cyclododecene was achieved, the best result being 56% selectivity to cyclododecene. Furthermore, in order to achieve even this poor level of selectivity to cyclododecene, superatomospheric pressure was employed.

We have now found that unexpectedly cyclododecatriene can be hydrogenated to cyclododecene with a selectivity in excess of by weight and with substantially complete conversion by carrying out selective hydrogenation at atmospheric pressure and a temperature within the range of from to 180 C. using gaseous hydrogen only as the hydrogen source and a palladium catalyst.

Other catalysts such as nickel, cobalt, iron, copper, platinum, rhodium or ruthenium will not afford satisfactory results.

The novel process according to the invention is much simpler than previously known processes in that (a) It does not require the use of a solvent, particularly a displacing solvent and/or a hydrogen transfer agent which is expensive and cannot be recovered in its original form and therefore cannot be re-cycled, and

(b) It does not require the use of expensive and possibly dangerous pressure equipment.

The present invention accordingly provides a hydrogenation process for the conversion of cyclododecatriene to cyclododecene in yields of at least 80% by weight which comprises heating cyclododecatriene with molecular hydrogen at a temperature in the range of from 130 to 180 C. at substantially atmospheric pressure, catalysing the reaction with a palladium hydrogenation catalyst in the absence of solvent.

The selective hydrogenation process of this invention is carried out by contacting the cyclododecatriene with the gaseous hydrogen at atmospheric pressure in the presence of the catalyst, at a temperature in the above-given critical range of from 130 to 180 C., a temperature of about C. being preferred in achieving the highest selectiv-.

ity, i.e., greater than 90% to cyclododecene. For optimum yields of cyclododecene, the amount of gaseous hydrogen which is employed is substantially two molecular proportions per molecular proportion of cyclododecatriene start ing-material in order that suflicient hydrogen is available to fully saturate two of the unsaturated bonds and that an excess of hydrogen is not available to attack the third unsaturated bond of the cyclododecatriene molecule.

The cyclododecatriene starting material can exist in a number of stereo-isomeric forms, the process of the invention not being limited to the hydrogenation of a particular stereo-isomer.

The cyclododeca 1:5:9-triene for use in the process of the invention may be the trans:trans:trans isomer or the cisztransztrans isomer or either of the other possible isomeric forms. The cyclododecatriene can be a pure or substantially pure compound, but it can also be a mixture of two or more stereo isomers, with or without other organic compounds, such mixtures being generally cheaper or more readily available starting materials, or in the form of a mixture with impurities or diluents; these impurities or diluents should, however, not inhibit the activity of the catalyst or otherwise have a deleterious effect on the course of the hydrogenation.

The palladium catalyst for the hydrogenation process of this invention can be unsupported palladium metal, for instance palladium black, or palladium oxide or a supported palladium catalyst, preferred supports being: charcoal, alumina, asbestos, pumice, an alkaline earth metal carbonate or sulphate, the atom number of which ranges from 40 to 60 inclusive, for instance calcium carbonate or barium sulphate, charcoal being particularly preferred. The palladium content of the catalyst should be about onetenth or higher in the case of unsupported catalyst, and should amount to about 1% to by weight, based on the total catalyst weight in the case of the supported catalyst. The proportion of palladium metal employed as catalyst in the process of this invention is preferably within the range of from 0.01% to 0.1% by weight based on the weight of cyclododecatriene starting material.

The presence of an added organic solvent is not necessary under the conditions of the process of the instant by gas/liquid chromatography. The total hydrogenation product amounted to 3.40 parts by weight. The results are given in Table 1 following Examples 2 to 5.

Examples 2 to 5 The procedure described in Example 1 was carried out using different reaction temperatures, namely 140, 150, 160 and 170 C., the reactants, catalyst and reaction conditions being otherwise the same as in the preceding example.

The iodine values and gas/liquid chromatographic analysis of the hydrogenation product obtained were determined and the results are given in the following Table 1, together with those of Example 1 and those of five comparative hydrogenations carried out by the same procedure except that reaction temperatures outside these specified in the present invention were used, namely and 200 C.

TABLE 1 Percent composition Reaction Iodine temperavalue Cyclo- Cyelo- Cyclo- Cycloture, C. dodecane dodecene dodecadodecadiene trlene Com arative runs:

152 10. 7 79. 6 9. 7 11.0 80. 2 8.8 150 147 6. 6 90. 6 2. 7 151 8. 7 84. 3 7. 0 Example 5 148 9. 5 84. 6 5. 9

invention in order to achieve high yields of cyclododecene.

The partial hydrogenation product obtained by the 40 process according to the invention can be used directly in the production of 1:12-dodecanedioic acid of a satisfactory degree of purity.

The following non-limitative examples further illustrate the present invention. Parts by weight shown therein 45 bear the same relation to parts by volume as do kilograms to liters. Percentages are expressed by weight unless otherwise stated.

Example 1 3.32 parts by weight of cis:trans:trans-cyclododeca- 1:5:9-triene and 0.015 part by weight of a 5% palladium/ charcoal catalyst (Type 17 catalyst, Johnson, Matthey and Co. Ltd., London) were placed in a reactor from which the air present was evacuated. The reactor was then heated to 130 C. and maintained at that temperature. Hydrogen was admitted to the reactor at atmospheric pressure and the reactor was shaken until 2 moles of hydrogen had been taken up per mole of the cyclododeca-l :5 :9-triene.

The hydrogen supply was then disconnected and residual hydrogen atmosphere was removed from the reactor. The reactor contents were allowed to cool to 20 C.; the catalyst was then filtered off and the iodine value of the filtrate was determined. The filtrate was also analysed The data in Table 1 demonstrate that in order to achieve selectivities to cyclododecene of 80% by weight, a temperature in the range of from about 130 to about C. is necessary.

Example 6 The procedure described in Example 1 was carried out using trans :trans:trans-cyclododeca-l :5 :9-triene instead ot the cisztransztrans isomer; the reaction temperature was 150 C., the catalyst and the reaction conditions otherwise being the same.

The iodine value and composition of the hydrogenation product obtained were determined as described in Example 1. The results were as follows:

Iodine value: 151 Composition:6.-0% cycl-ododecane, 89.5% cyclododecene,

4.5% cyclododecadiene, no cyclododecatriene.

Examples 7 to 9 The procedure described in Example 1 was carried out using a reaction temperature of 150 C. but using different palladium catalyst, the reactants and reaction conditions otherwise being the same.

The iodine values and compositions of the hydrogenation product obtained were determined as described in Example 1. The results are shown in the following table:

- Y 6 These results showed that excellent selectivity of hydrotor until two molar proportions of hydrogen had been genation to the mono-ene was achieved using palladium/ taken up per molar proportion of the triene initially charcoal and palladium/alumina catalysts. present. The pressure in the reactor was maintained at Examples 10 to 14 atmospheric pressure throughout the hydrogenation.

The hydrogen supply was then disconnected and the The Procedure described in p 1 was Carried residual hydrogen atmosphere was flushed out of the Out for Comparative P p Only to hydfogenate cisi reactor with a stream of nitrogen. The reactor was then trans:trans-cyclododeca-lg5g9-triene using catalysts other l d Th t l was fil d f h h d than a Palladium ys The Catalysts, reaction tion product and iodine value and composition of the peratu-re, pressure and reaction times are given in Table filtrate wa determined.

3, the procedure and analyses being carried ou Other- The product had iodine value 147 and the following Wi$ea$d$0fibedinEXamP1e composition as determined by gas/liquid chromatog- TABLE 3 raphy:

Cyclododecane8.4

' "Reaction Initial Final Reaction i Cyclododecene-87.2% E 0 t1 t t t x a 8 Y5 air-3 215:1 32: 25x 33: (11 5338) Cyclododecad1ene4.4%

Pheres) Pheres) Cyclododecatrienenil.

100 l 55 5 16 The above procedure was repeated using the same pro 100 60 0 16 portions of reactants and process conditions but eflect- 150 1 1 150 80 60 20 mg the hydrogenation in an autoclave at a pressure within pp l 120 55 0 16 the range of from 10 to 20 atmospheres.

' The product had an iodine value of 148 and the fol- The iodine values and the compositions of the respeclowing composition as determined by gas/liquid chromative hydrogenation products are given in Table 4. tography:

TABLE 4 Cyclododecane11.1% Cyclododecene-79. 1 Percent composition Cycloclodecadiene8.8% Iodine Example value Cyclo- Cyelo Cyclo- Cycle Cyclododecatnene mldodedodedodecadodecacane eerie diene triene E l 16 t 18 166 24 46 24 7 The procedure described in Example 1 was carried fig g? 5 g; 5 8 1 out using the different proportions of palladium in the 263 palladium/charcoal catalyst as set out in Table 5, the 166 13 66 18 3 hydrogenations being carried out at 150 C. and at atmospheric pressure. The results are given in Table 5, The results in Table 4 show that catalysts other than the procedure and analyses being carried out as depalladium lead to only poor selectivity to cyclododecene. scribed in Example 1.

TABLE 5 Percent composition Percent Iodine Example Pd on value Cyclo- Cyelo- Cyclo- Cyclocharcoal dodeeane dodeceue dodecadodecadiene triene This is true for the use of nickel as catalyst even when From the results in Table 5 it can be seen that a palthis catalyst is employed under the preferred process conladium content of about 5% of total palladium/ charcoal ditions of the present application. catalyst leads to optimal selectivity to cyclododecene.

Example 15 Examples 19 to 25 The procedure described in Example 1 was carried out for the purposes of comparison only using the various catalysts listed in Table 6, the hydrogenations being car- 324 parts by weight of cis:transztrans-cyclododeca- 1:5:9-triene and 2 parts by weight of the 5% palladium/ charcoal (Type 17) catalyst were placed in a re ctor, ried out at 150 C. and at atmospheric pressure. which was then evacuated to remove air and heated to The results are given in Table 6, the procedure and 150 C. Hydrogen gas was then admitted to the reacanalyses being carried out as described in Example 1.

TABLE 6 Percent composition Metal; percent Iodine 1 Mixed metals containing 2.5% of each metal.

Again the unsatisfactory selectivities to cyclododecene achieved when catalysts other than palladium are used can be seen from the results in Table 6. It should be noted however that when a portion of the platinum and ruthenium catalysts is replaced by palladium, the use of such mixed catalysts results in substantial increases in selectivity to cyclododecene.

We claim:

1. A process for the production of cyclododecene consisting essentially of heating cyclododecatriene with molecular hydrogen at a temperature in the range of from 130 to 180 C. at atmospheric pressure catalysing the reaction with a palladium hydrogenation catalyst in the absence of a solvent, thereby to obtain a reaction product containing at least 80% by weight of cyclododecene.

2. A process as defined in claim 1 wherein the proportion of molecular hydrogen employed is substantially two molecular proportions per molecular proportion of cyclododecatriene.

3. A process .as defined in: claim 1 wherein the hydrogenation temperature is about 150 C; I v V H 4. A process as defined in claim 1 wherein the catalystconsists of palladium supported on charcoal.

5. A process as defined in claim 4 wherein the proportion of palladium in the palladium/charcoal catalyst is about 5% by weight.

7 References Cited H UNITED STATES PATENTS Arrigo 260666 D L R E G N a Yimfl y Examin r- 2 V. OKEEFE, Assistant Examiner; 

